Devices for delivering a useful agent including drugs are known to the prior art. For example, U.S. Pat. No. 3,545,439 issued to Gordon W. Ducan discloses a medicated annular device designed as a resilient individual ring that can be made from various polymeric materials. The device is used for intravaginally releasing a medicament. The device optionally contains a tension spring for keeping it in the vagina. In U.S. Pat. No. 3,920,805 patentee Theodore J. Roseman discloses a solid, polymeric device that has a nonmedical central core and an encircling medicated coating made of a polymer. The device releases drug by diffusion and in a preferred embodiment, the device is ring-shaped with a flat tensioning spring molded in the nonmedicated central core. In U.S. Pat. No. 3,991,760 patentees James L. Drobish and Thomas W. Gougeon disclose a device for use in the vaginal canal. The device consists of a plurality of individual containers connected by a seal fin in a plane perpendicular to the plane of the device. The containers have a microporous wall for releasing a surfactant in the vagina. In U.S. Pat. No. 4,012,496, patentees Gisela Schopflin, Gerhard Laudahn, Barbara Mirhe, Heidemane Hartmann and Fredt Windt disclose a device having a major and minor portion. The major portion consists of a ring having at least a portion of its surface adapted to mate with a minor medicament containing segment. The minor segment fits into a pocket-like indentation in the major portion. The minor segment releases medicament in the vagina channel over time.
While the above-described devices are useful for certain applications and environments, there are serious disadvantages frequently associated with these devices that limit their use. For example, one disadvantage is the devices may have many parts made of different materials which require individual molding and curing fabrication procedures to make the devices. These fabrication procedures tend to restrict the shape of the devices and the use of different parts tends to produce rigid devices. The devices usually are designed for housing a single agent and the amount of agent that can be loaded into the devices is limited by its restricted design and parts. Also, the devices have a constant release surface and they cannot be adjusted for different needs. Those versed in the delivery art will recognize that if devices can be provided that are essentially free from the above tribulations, such devices would be a valuable advancement and a useful improvement in the delivery art.